Mortgage Loans (Notes)	12 Months Ended
Dec. 31, 2013
Mortgage Loans [Abstract]
Mortgage Loans	Mortgage Loans In connection with the previous sale of One Park Ten, the Company had seller-financed a $1.5 million note receivable that bore interest at 7.3% per annum on an interest-only basis through maturity in June 2012. On April 2, 2012, the borrower repaid the note receivable and all accrued interest in full. On April 10, 2012, the Company transferred its rights, title and interest in the B participation piece (the "B piece") of a first mortgage loan secured by an 844,000 square foot office building in Dallas, Texas known as 2100 Ross. The B piece was purchased at an original cost of $6.9 million in November 2007. The B piece was originated by Wachovia Bank, N.A., a Wells Fargo Company, and had a face value of $10.0 million, a stated coupon rate of 6.1% and a scheduled maturity in May 2012. During 2011, the Company recorded a non-cash impairment loss on the mortgage loan in the amount of $9.2 million, thereby reducing its investment in the mortgage loan to zero. Under the terms of the transfer, the Company is entitled to certain payments if the transferee is successful in obtaining ownership of 2100 Ross. During the third quarter of 2012, the transferee successfully obtained ownership of 2100 Ross and as a result the Company received a $500,000 payment, which is classified as recovery of losses on a mortgage loan receivable on the Company's Consolidated Statements of Operations and Comprehensive Income. On June 3, 2013, the Company issued a first mortgage loan to an affiliate of US Airways, which is secured by a 225,000 square foot office building in Phoenix, Arizona known as the US Airways Building. The $3.5 million mortgage loan has a fixed interest rate of 3.0% and matures on December 31, 2016.

Mortgage Loans

In connection with the previous sale of One Park Ten, the Company had seller-financed a $1.5 million note receivable that bore interest at 7.3% per annum on an interest-only basis through maturity in June 2012. On April 2, 2012, the borrower repaid the note receivable and all accrued interest in full.

On April 10, 2012, the Company transferred its rights, title and interest in the B participation piece (the "B piece") of a first mortgage loan secured by an 844,000 square foot office building in Dallas, Texas known as 2100 Ross. The B piece was purchased at an original cost of $6.9 million in November 2007. The B piece was originated by Wachovia Bank, N.A., a Wells Fargo Company, and had a face value of $10.0 million, a stated coupon rate of 6.1% and a scheduled maturity in May 2012. During 2011, the Company recorded a non-cash impairment loss on the mortgage loan in the amount of $9.2 million, thereby reducing its investment in the mortgage loan to zero. Under the terms of the transfer, the Company is entitled to certain payments if the transferee is successful in obtaining ownership of 2100 Ross. During the third quarter of 2012, the transferee successfully obtained ownership of 2100 Ross and as a result the Company received a $500,000 payment, which is classified as recovery of losses on a mortgage loan receivable on the Company's Consolidated Statements of Operations and Comprehensive Income.

On June 3, 2013, the Company issued a first mortgage loan to an affiliate of US Airways, which is secured by a 225,000 square foot office building in Phoenix, Arizona known as the US Airways Building. The $3.5 million mortgage loan has a fixed interest rate of 3.0% and matures on December 31, 2016.